1. Field of the Invention
The present invention relates to a brake pressure control system such as an anti-skid braking control system or a traction control system for a motor vehicle, and more particularly to a brake pressure control system for controlling a hydraulic brake pressure based on a brake pressure control gradient which is calculated from a quantity indicative of a slipping or skidding condition of a wheel.
2. Prior Art
Japanese Patent Publication No. 59(1984)-20508, for example, discloses an anti-skid braking control system. In the disclosed anti-skid braking control system, the rotational speed and acceleration of a road wheel of a motor vehicle are detected, a plurality of reference speed or acceleration levels are calculated, and the detected rotational speed or acceleration is compared with each of the reference levels to select an actuator control mode for the control of a hydraulic brake pressure.
With the conventional anti-skid braking control system, a control gradient for the hydraulic brake pressure is not continuous while the rotational speed or acceleration of the road wheel is of continuous nature. As a result, the brake may be excessively released or applied, causing vibrations of the motor vehicle which impair the riding comfort of the passengers. The braking efficiency of the prior anti-skid braking control system still remains to be improved.